The present invention is mainly encompassed within the framework of food product packaging and, more specifically, in the meat industry field. There is a large variety of products that are wrapped in laminations for their processing, handling and/or preservation. The use of the lamination is supplemented in many cases with a tubular net and is particularly applicable to special products where the appearance of the product is important.
The lamination and net assemblage form a wrapping in which the main functions of the lamination are to prevent excessive evaporation during the heating process, permit smoking, provide sheen, colour and appearance to the surface of the product, facilitate the removal of the net and also of the actual lamination in the event of this not being edible, and in addition it should be soft enough to allow the net to transmit its imprint to the product, giving it a typical appearance. The use of the lamination and net further permits the use of diced meat and cuts of different sizes and qualities, including meat emulsions and fine pastes, either on their own or combined with the former in different proportions, as the lamination and net assemblage confines and secures the product inserted in its interior until it coagulates and binds during the heating process, thereby permitting the making of reconstituted meat products.
At the present time laminations and nets are applied in the food industry either manually or by mechanical means. For this purpose the laminations are supplied either in cut sheets or else in rolls of varying length that may range from 5 to 250 meters. The nets come in roll form with minimum lengths of 50 meters. A manual form of application consists of wrapping the food product with the laminations and covering it with the net by sliding it through the inside of a hollow cylinder or metal tube that acts as a carrier for a certain amount of tubular net, which has been folded or compressed on it coaxially, and drawing the product out of the other end of the cylinder together with the net with which it is thereby covered. This procedure is described in U.S. Pat. No. 4,621,482 (Crevasse, Gammon, Sullivan 1986). An even more elementary procedure is described in U.S. Pat. No. 4,719,116 (Crevasse 1988).
The mechanical procedure is carried out by means of so-called “applicators”, which execute the wrapping of the product with the lamination and with the net at the same time. A typical applicator consists of a lamination roll holder, a device for forming a cylinder from the lamination, and a tube running through the interior of the lamination tube formed and through which the food product is passed. A tube in which a given amount of net is loaded is arranged concentrically to the foregoing assemblage. The end of the tube formed of the lamination and the end of the compressed portion of net are taken in conjunction to a point ahead of the open end of the insertion tube and are closed together by means of a clip, knot or some other appropriate system, so that the system is ready to be inserted either by mechanical pumping or else by means of a hand or air-operated piston. On being forced out of the tube, the product pulls the lamination and the net at the same time, so that in this way it is wrapped by both. This procedure and the device for carrying it out are described in U.S. Pat. No. 4,910,034 (Winkler 1990) and U.S. Pat. No. 4,958,477 (Winkler 1990), respectively.
To compress the nets on the outer coaxial tube which is used for forcing in the meat according to the traditional method, a loader device is employed. This consists of a tube with a cone-shaped termination on one end, which facilitates the loading of the net, and of a ring-shaped loader device with a diameter slightly larger than that of the tube, provided with a pair of handles so as to be able to handle it manually. Its interior portion has a series of teeth angled in the direction of loading, so that, once disposed around the net tube and the latter has been threaded into the tube, it draws the net when pushed from the end to the base and slides over the net due to the orientation of its teeth, when the opposite movement is executed. The tubes used in the procedures described above are of large diameter, with the result that the elastic net is loaded tightly stretched and exerts considerable pressure on the tube. On account of this only a small amount of net may be stored on the tube, as the actual net stored at the end of the tube prevents more from being loaded in that area. This also means that for the unloading or unfolding of the net it is necessary to exert a certain force, so that the unloading or unfolding is not performed smoothly. In the same way, as the tube goes on being loaded with net, the front of the net loaded moves further away from the end of the tube, so that the back and forth movements of the loader become shorter and shorter and the amount of net loaded is smaller, making the manual loading of the net increasingly slower and more laborious.
This operation can also be done mechanically. Devices for this purpose are described in U.S. Pat. No. 5,273,481 (Sullivan 1993) and U.S. Pat. No. 4,924,552 (Sullivan 1990).